Those who reject the doctrine of eternal security tend to place more emphasis on the subjective experiences of "professing" Christians than the objective truth of Scripture. They may know someone who was baptized, repeated a prayer or responded to an altar call, then later rejected the faith or turned to a life of habitual sin. These experiences become their proof that salvation has no assurance. But is there any way to know if these people were born again? Judging someone’s spiritual condition is risky because no one can see a person’s heart. Opponents of assurance focus on man’s failures rather than on God’s divine power. Such misunderstandings can be overcome by discarding human reason and accepting divine revelation. Faith should not rest on the wisdom of man but on the power of God (1 Cor. 2:5).

The "eternal" Gospel (Rev. 14:6) of our "eternal" God (Rom. 16:26) promises every believer "eternal" life (1 John 5:13) and "eternal" glory (1 Pet. 5:10) in His "eternal" kingdom (2 Pet. 1:11). The "eternal" King (1 Tim. 1:16) called salvation "eternal" (Mark 16:20) because He has given believers "eternal" comfort (2 Thes. 2:16) by obtaining "eternal" redemption through the "eternal" Spirit who guarantees an "eternal" inheritance (Heb. 9:12-15; Eph. 1:14). According to God’s "eternal" purpose (Eph. 3:11), every believer has been saved from "eternal" judgment (Heb. 6:2), "eternal" destruction (2 Thes. 1:9) and "eternal" punishment in the "eternal" fire (Mat. 25:41, 46).

Eternal life is not only an infinite quantity of time (people in hell will live forever), but an eternal quality of life. It is an intimate relationship with Jesus whereby His life and divine nature is placed in every believer and every believer is in Him (2 Pet. 1:4; 1 John 5:20). This life begins at the second birth when those who were dead in their sins are made alive in Christ (Eph. 2:4). Eternal life is everlasting because the very life of Christ (who can never die again) has been imparted to believers (Rom. 6:9). But this leads to a provocative question. Knowing that sin is what brings spiritual death to the soul, what keeps Christians from dying again when they sin after their conversion? The apostle Paul gives the answer. It is because God no longer counts sins against those who have trusted Jesus as their substitute (Rom. 4:8; 2 Cor. 5:21). God laid all their sins, past and future, on Jesus (Isaiah 53:6). Our kinsman redeemer "bore our sins in His body on the cross, that we might die to sin and live to righteousness" (1 Pet. 2:24). "With His own blood He entered the Most Holy Place once for all, having obtained eternal redemption" (Heb. 9:12). Everyone redeemed has been bought with the precious blood of Jesus and now belongs to Him. Eternal redemption and eternal security are thus one and the same.

Those who reject eternal security must explain why they do not also reject everything else described as eternal, such as the eternal triune God and His punishment for unbelievers. They must also be able to answer—with Scripture—some other relevant questions. Can those who have been redeemed from under the curse of the law be placed back under it (Gal. 3:13; 4:5)? Can one, who has been born again of incorruptible seed, die again (1 Pet. 1:23)? Can a new creation return to what has passed away (2 Cor. 5:17)? Can one who has been perfected forever be found imperfect (Heb. 10:14)? Can those whom God delivered from the power of darkness be sent back (Col. 1:13)? Can those who have been made complete in Christ become incomplete (Col. 2:10)? Can those who were saved without merit or human effort be lost because of demerits or human failure (Eph. 2:8-9)? Does any man have the ability to undo a sovereign act of Almighty God (Rom. 8:28-39)?

"Truly, truly, I say to you, he who hears My word, and believes Him who sent Me, has eternal life, and does not come into judgment, but has passed out of death into life (John 5:24). "My sheep hear My voice, and I know them, and they follow Me; and I give eternal life to them, and they shall never perish; and no one shall snatch them out of My hand" (John 10:27-28). Jesus also promises never to cast out or lose anyone that His Father gives Him (John 6:37, 39). The promises of Jesus to all believers are clear and are guaranteed by His divine power and attributes. Having received eternal life, the sheep will follow the Shepherd who will keep them and protect them. Jesus promises they will never be judged for their sins, will not experience spiritual death, shall not perish and will never be cast out or lost. How can Christians say they trust Jesus and not believe His promises?

God the Father has caused His children to be born again to a living hope. They are now protected by His power and will obtain an inheritance which is imperishable and reserved for them in heaven (1 Pet. 1:3-5). This inheritance has been securely guaranteed by the sealing of the Holy Spirit (Eph. 1:11-14). The Father, who calls believers into fellowship with His Son, is faithful and will confirm them until the end (1 Cor. 1:8,9). He promises to glorify those He justifies (Rom 8:30). God’s children have this assurance: "He who began a good work in you will perfect it until the day of Christ Jesus" (Phil. 1:6). On that spectacular day, all believers will be revealed with Him in glory (Col. 3:4). Everyone who has trusted Christ can have the same confidence as Paul who wrote: "I know whom I have believed and am persuaded that he is able to keep that which I have committed unto him against that day" (2 Tim. 1:12).

Believers also have the assurance that God’s gifts and calling are irrevocable (Rom. 11:29). The amazing gifts God gives to repentant sinners include eternal life (Rom. 6:23), the Holy Spirit (Acts 10:45) and the righteousness of Jesus (Rom. 5:17). Those who have received these gifts will never again be separated from God and never come into judgment for their sins. Opponents of assurance will say that people can give back the gifts or throw them away. But where is the Scriptural support for this? God has credited the gift of righteousness to the believer’s account. Does man have access to God’s books to change His accounting?

The Lord knows those who are His and everyone who names the name of Christ must depart from iniquity (2 Tim. 2:19). But what does God do with any of His children who persist in sinning? He chastens them, as a loving Father, so they will not be condemned along with the world (1 Cor. 11:32). God’s chastening has a purifying effect on those who do not judge themselves. His discipline will continue until there is repentance or until He calls them home. Those who fall away or fall into habitual sin without God’s chastening were never His children (Heb. 12:6-9).

The Roman Catholic Catechism (CCC) teaches that Catholics lose their salvation when mortal sins are committed (CCC, para. 1035). Catholics must do works of penance and merit enough grace to regain their salvation (CCC, para. 1456, 2027). Needless to say, Catholics can never be sure about their eternal destiny because, whenever man is involved in attaining and/or preserving his salvation, there can never be assurance. However, when man forsakes all efforts to save himself and believes the objective truth of the Gospel, he will be more certain of living eternally in heaven than one more day on earth. There is no way a mortal man can do maintenance on an eternal gift from God. Paul wrote, "For this reason it is by faith, that it might be in accordance with grace, in order that the promise may be certain to all" (Rom. 4:16).

John wrote his first epistle to those "who believe on the name of the Son of God, in order that you may know [Gk. oida] you have eternal life (1 John 5:13). The Greek word "oida" refers to a positive, absolute knowledge. True believers can rejoice in their salvation with absolute certainty and peace. The question for professing Christians is not "Will God will keep His promises?" but "Have I been saved by grace through faith in Jesus Christ alone?" This means forsaking all other attempts at salvation through sacraments, good works, indulgences, purgatory, the sacrifice of the Mass, obeying the Law and the intercession of Mary.